Electronic products typically have electrical circuitry implemented on a circuit substrate, such as a printed circuit board. Portions of the circuitry may be adversely affected by electromagnetic interference, electrostatic discharge, and other environmental factors. Additionally, many electrical components generate electromagnetic interference which may adversely affect the operation of other portions of the circuitry. Consequently, such products often incorporate shields, or other protective devices, to protect critical portions of the circuitry, or specific components.
A metallized enclosure, such as a metal can, is commonly used as a shield for protecting sensitive electrical components. During assembly of the electronic product, the shield is placed over the circuitry or components to be protected and secured to the circuit substrate, such as by soldering and the like. A one-piece shield which fully encloses the components is relatively simple and inexpensive to manufacture. However, once secured to the circuit substrate, the protected components are inaccessible for testing, such as by visual inspection, and for analysis and repair without physically removing the shield. If the shield had been soldered to the circuit substrate, removal of the shield might involve reheating of solder and manipulation of the shield which may result in the creation of defects by inadvertently altering other portions of the electrical circuitry. Another option involves the use of a two-piece shield design. The two-piece shield includes a hollow-top frame, and a corresponding cover which fits over the frame. The frame provides a mounting platform support for the cover. The shield is completed when the cover is mounted on the frame. Ordinarily, the cover is mounted late in the assembly process so that the protected components is accessible for testing, such as by visual inspection, and for analysis and repair without the removal of the frame.
Although, solving the problem of access to shielded components, the two-piece shield with the hollow-top frame has some problems. First, the frame is difficult to handle by conventional pick and place machine using gripping techniques such as vacuum suction. For example, multiple vacuum nozzles may be needed to securely grip the piece for placement. Additionally, the frame tends to lack rigidity because of its hollow top. It is desirable to provide a shield which facilitates the testing, analysis, and repair of components during the manufacturing process. However, such a shield should permit ease of handling for assembly. Accordingly, there exists a need for a new shield design.